You're likely not safe

2. Once installed fire it up and hit "Begin testing" - it'll run through your phone to see whether you're at risk.

3. If you're at risk, head to Settings > About Phone > Software Updates to see if you've been pushed an update which could potentially resolve the issue.

4. If you are vulnerable we recommend not opening video MMS from strange numbers and also turning off Auto Retrieve SMS when using Hangouts as your main text app.

We ran the app on our LG G4 and were told it is vulnerable to CVE-2015-1539, CVE-2015-3827 and CVE-2015-1538.

We also tried on the HTC One M9, but the app couldn't complete the test. If you experience the same problem download Stagefright Detector by Lookout, as it runs the same test. We were told our One M9 is also at risk.

So far there's no quick fix to make sure you're all OK. It's a case of waiting for Google and manufacturers to roll the update out further.

Samsung, LG and Google have now pledged to roll out monthly security updates to try to combat Stagefright and any other flaws found in the Android OS.

If you're using one of these manufacturers devices it'll be worth keeping an eye on your updates to see when they roll out the fix for Stagefright.